Chain grate



F. S. SIMPSON CHAIN CRATE Jan. 11, A1955 Filed April 30, 1952 2 Sheets-Sheet l /P fray/vins Jan. 1l, 1955 F. s. SIMPSON CHAIN GRATE 2 Sheets-Sheet 2 Filed April 50, 1952 United States Patent O CHAIN GRATE Franklin Stanley Simpson, Alton, Ill., assignor to Illinois Stoker Company, Alton, Ill., a corporation of Illinois Application April 30, 1952, Serial No. 285,183

4 Claims. (Cl. 11040) This invention relates to furnace grates and, more particularly, to chain links for forming furnace grates of the endless chain type.

The so-called chain-grate furnace has a grate formed as an endless belt type of conveyor, and material that is to be burned or heated is dumped upon the upper reach of the grate at the rear end and, after burning, is discharged at the forward end of the upper reach. In utilizing the chain-grate furnace for heating and burning refuse, certain difficulties are encountered as a result of the tendency for the refuse to enter between the links forming the upper reach of the grate. Such refuse may lodge in the grate, or after passing through the upper reach, may fail to pass through the lower reach. In the former instance, the draft passages become clogged with adverse effects upon combustion, and in the latter instance, the refuse is not only improperly discharged at the rear end of the grate but may be carried into the drive sprocket. It is accordingly an object of this invention to provide a chain grate wherein entry of refuse between the ends of adjacent links is effectively prevented, and wherein the possibility of refuse entering draft openings at the sides of the links is minimized. Further, it is an object of the invention to prevent material that may enter the draft passages from becoming lodged therein.

Among the several other objectives of this invention are the provision of chain links adapted for assembly both laterally and longitudinally by means of conventional linking rods; the provision of chain links of the class described wherein head portions of generally rectangular plan outline are assembled in longitudinal and transverse alignment; the provision of links of the above character wherein ow of air is directed vertically beneath the head portions along an upper reach of the chain grate; the provision of side links adapted to provide for protected capping of linking rods; and the provision of links of the above nature which are of simple, rugged construction.

Additionally, the chain grate of this invention is ideally adapted, because of its stepped surface, to drag material through the feed gate between the hopper and the furnace proper. With iinely granulated material, such as coal, this is not a problem, but refuse may tend to lump together. Accordingly it is an object of the invention to provide means for breaking up such material as refuse against the feed gate so that the material is conveyed from the hopper into the furnace.

In accomplishing these objectives, I provide a chain link having a longitudinal vertically-disposed web upon which are formed forward and rear rod bearings. This web supports a head portion of generally rectangular plan outline and asymmetrically positioned on the web so as to overhang substantially on one side thereof, The head portion further is formed with a stepped configuration in side elevation with the step rising in a forward direction relative to the contemplated movement of the link. Provision is made for receiving a rear end of a next leading link between the forward end of the head portion and the forward rod bearing portion so that the head portions of longitudinally adjacent links are overlapped. Transverse batiles extend outwardly from the longitudinal web about the full width of the head portion immediately above the rear rod bearing and transversely cooperate with the rod bearings of assembled links to prevent longitudinal flow of air through the 2,699,130 Patented Jan. 11, 1955 grate. Longitudinally spaced bosses at the sides of the head portion are aligned with the rod bearings so that an air draft gap is formed between transversely adjacent links. Additional ow of draft air is provided by draft passages at the sides of adjacent links, which passages are of downwardly increasing cross section in order to prevent solid material from lodging therein.

Other features of the invention will be in part described in and in part apparent from the following detail description taken in connection with the accompanying drawings, in which:

Fig. 1 is an oblique view of a chain-grate link of this invention;

Fig. 2 is a top plan View of a part of a chain grate formed from the chain-grate links of Fig. 1;

Fig. 3 is a side elevation of Fig. 2;

Fig. 4 is a section taken on the line 4--4 of Fig. 3; and

Fig. 5 is a right end view of Fig. 3.

Referring to the drawings, there is shown a part of the upper reach or strand of a chain grate which may be of varying length or width depending uponythe size of the furnace. This grate is made up as a wide chain from right-handed and left-handed intermediate links 1 and 3, respectively, and the chain is trained around a plurality of sprockets or drums to provide upper and lower reaches. As is known in the art, the chain is continuously driven from one or more of the sprockets so that the upper strand will move from one end herein referred to as the rear, to the other end, herein the forward end, While conveying burning material through the furnace. Upon completion of the heating or burning, the material arrives at the forward end and is discharged by gravity. In continuing around the curved surface or contour of the drum or sprockets, it is important that the chain present a closed surface to prevent material from dropping through. It will be understood that refuse may contain bolts, scrap iron, bed springs, etc., hence it is important to present a closed grate not only along the upper strand, but also at the ends. Otherwise, metal objects entering the grate at the ends might lodge therein and prevent the proper functioning of the chain when it straightens out. The sides of the chain grate are trimmed with side links 5, which may cooperate with fixed guides forming a part of the furnace.

Each of the intermediate links comprises a longitudinal vertically-disposed web 7 formed at its ends with forward and rear apertured shoulders 9 and 11, respectively. The forward aperture 9 serves as a rod bearing permitting the rear rod bearing 11 of a next link to be linked therewith in axial abutting relation on a conventional linking rod 13. At the top of the web 7 there is an overhanging platen or head portion 15, which is of generally rectangular plan outline. The platen 15 is asymmetrically arranged on the longitudinal web so that there is a large overhang 17 on one side of the web and a relatively small overhang 19 on the other side thereof. Herein, the right and left links 1 and 3 differ merely in the direction of the primary overhang 17. In side elevation, the platen 15 has a stepped configuration which rises in a forward direction. The forward end 21 of the platen extends over the forward bearing 9 with a substantial spacing therebetween, and the central part 23 of the platen declines rearwardly to a curved end 25 which extends over the rear bearing 11 with a relatively small space therebetween.

Between the platen and the forward bearing 9, the web 7 is recessed to provide a slot 27, which is adapted to receive the end 25 of an immediately preceding link. The upper edge of the slot 27 is in the shape of an arc concentric with the bearing 9 and the rear end 25 of the platen is curved on an arc concentric with the rear bearing 11, both arcs being of substantially equal but slightly different radius, in order to produce a close overlapped fit between the ends of adjacent links and thereby prevent material conveyed by the upper reach from entering between these ends.

In assembling the links, right and left links are staggered longitudinally and laterally with the rod bearings being laterally overlapped, as best shown in Fig..4. A forward bearing 9 of one link coaxially abuts with a rear bearing 11 of another link, and the ends of these links overlap above the bearings. The axial dimensions of the bearing shoulders are correlated with the width of the platen so that a small gap 28 appears between laterally adjacent links. The long narrow shape of this gap 28 provides for proper draft yet prevents material from falling therethrough. Additional draft is provided by passage-forming recesses 29 along the sides of the central part of the platen. The recesses 29 of adjacent links align, and are of downwardly increasing cross section so that material entering at the top does not lodge therein.

Draft air is uniformly distributed over the lay of the grate in a transverse direction by the bafiling effect of the longitudinal webs 7, which extend between the bearings adjacent one set of the recesses 29. Protection against non-uniform draft in a longitudinal direction is afforded by a transverse baffle arrangement formed in part by the axial abutted bearings 9 and 11, and in part by the transverse webs 31 and 33. These webs 31 and 33 extend from opposite sides of the longitudinal web 7 across the platen and above the bearings. The longer web 31 of a link is adapted to extend over and have a reasonably close fit with the forward bearing 9 of a following link, so that the webs and bearings together form a transverse bafiie. The above arrangement also provides a drive tooth recess for proper cooperation with the usual sprockets, the intermediate links serving as drive links.

The transverse webs project slightly beyond the sides of the associated platen for alignment with the axial ends of the bearing shoulders 9 and 11. These projections are then continued at the sides of the platen in a vertical direction by side bosses 35 and 37 at the rear and front, respectively. Consequently, when the links are assembled, transverse baffling is provided completely up to the top surface of the links.

The side links 5 are generally similar to the intermediate links 1 and 3, but differ in that forward and rear bearings 41 and 43 thereof are laterally offset with respect to one another and connected by a longitudinal web 45 which turns outwardly in a rearward direction, such being permissible because these side links do not cooperate with the sprockets. The rear rod bearing 43, moreover, is located intermediate the sides of the head portion 47, so that there is provision on the outer side for permitting an end of a linking rod 13 to be capped. A capping washer 49 is secured by a cotter pin 51 on the end of the linking rod in a protected position beneath the overhanging platen 47. The transverse web arrangement differs in that an inner transverse web 53 extends over the rod bearings and an outer transverse web 55 extends from the central portion of the longitudinal web 45 to the outer edge of the platen 47. It will be understood that the left hand side links (not shown) are inversions of the right hand side links, insofar as the web and bearing arrangement is concerned.

From the foregoing description, it is apparent that those skilled in the art will understand the structure, function and mode of operation of the invention herein disclosed, and appreciate the advantages thereof. Although one embodiment has been disclosed in detail, it is to be understood that the invention is not limited thereto, but the drawings and description thereof are to be understood as being merely illustrative. It is realized that many modifications and variations will present themselves to those skilled inthe art without departing from the spirit of this invention or the scope thereof as set forth in the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

l. A chain grate comprising a plurality of chain links each having a longitudinal vertical web and a laterallyoverhanging head portion supported upon said vertical web with its ends overlying the ends of said web, the vertical webs of the links being laterally overlapped at their ends and pinned together, and the head portions of said links being in longitudinal and lateral alignment and being vertically overlapped at their ends.

2. A chain grate as set forth in claim 1, wherein each link has its vertical web extending along one side of the head portion, alternate links in longitudinal alignment having their head portions laterally overhanging their webs in opposite directions and accommodating therebeneath the bearings of longitudinally adjacent links.

3. A chain grate link comprising a longitudinal vcrtical web formed with front and rear rod bearings at its opposite ends, a head supported upon said vertical web and having vertically-offset front and rear portions overlying said rod bearings and connected by an inclined central portion, the lower surface of said front head portion being spaced from said front rod bearings and being in general alignment with the upper surface of said rear head portion, said vertical web being formed with a forward recess having an upper edge defined generally by an arc concentric with said first rod bearing, said head having a rear projection formed with an upper surface defined by an arc concentric with said second rod bearing and of a radius generally corresponding with the radius of said first arc.

4. A chain grate link comprising a longitudinal vertical web formed with front and rear rod bearings at its opposite ends, a head supported upon said vertical web and having vertically-offset front and rear portions overlying said rod bearings and connected by an inclined central portion, the lower surface of said front head portion being spaced from said front rod bearings and being in general alignment with the upper surface of said rear head portion, said head having baffle-forming bosses at the sides of its front and rear portions, said bosses being in vertical alignment and integral with said front and rear rod bearings.

References Cited in the file of this patent UNITED STATES PATENTS 1,206,197 Bennett et al Nov. 28, 1916 1,476,337 Holt Dec. 4, 1923 1,574,276 Bennis Feb. 23, 1926 1,600,868 Courtney Sept. 2l, 1926 1,807,502 Bennis May 26, 1931 1,812,125 Trainer June 30, 1931 1,963,789 Holt June 19, 1934 2,233,542 Lloyd Mar. 4, 1941 FOREIGN PATENTS 232,666 Great Britain Apr. 21, 1925 228,925 Great Britain June 3, 1926 

